Wire connectors are used for joining wires and cables quickly and for covering the ends of the joined wires to reduce the potential for the wires to touch other wires, metal surfaces or people. Wire connectors are manufactured in various forms. In their earliest form, the sleeve of a connector was made of porcelain and was normally provided with grip-enhancing flutes. The narrow end of the sleeve was enclosed and at times was formed to receive a hexagonal wrench.
Modem connectors are typically made of plastic or other non-electrically conducting material and have a tightly coiled spring inside that helps to hold the wires, to twist them on insertion into the connector, and to assure good electrical contact among the wires.
When joining wires, the ends of the wires are first stripped of insulation and may be twisted or bunched together. The bared ends are inserted into the connector and the connector then twisted as the wires are pushed into it. The spring inside the wire connector may be made with a square or diamond-shaped cross section so that it acts as metal threading on the inside of the connector, resisting accidental loosening of the connector.
Although they serve a safety function and are handy, present wire connectors are not totally satisfactory. Even in circumstances requiring a modest amount of wiring, a junction box can have a bewildering array of wire connectors, each connecting two or three or more wires. Identification of the right wire in such a box can be a time consuming task that is not always immediately successful. If the wires are to be tested to determine, for example, if they are receiving current, the wire connector should be removed, because inserting a test probe under the cap will not assure that good contact has been made. However, when the wire connector is removed, the wires it covered are then exposed. Moreover, the circuits will be disturbed in many cases as well.
There have been a number of attempts to address the problems of wire connectors. One such attempt was made by Legerius et al. in U.S. Pat. No. 4,883,921. They describe a wire connector having a hole in the top that is intended to provide access to the interior for testing, thus obviating the need for removal of the connector. A metal ball located near the top of the body and resting on the metal spring is intended to allow contact between a test probe and the wires inside. However, this device is also unsatisfactory. For example, dust and dirt accumulating in the hole at the top of the connector body can prevent good contact with the ball.
Thus there remains a need for a more effective wire connector.